Qantas is seeking to permanently block publication of a planned book by long-time speechwriter for Qantas chief executive Alan Joyce, Lucinda Holdforth. The airline claims the manuscript, Fighting Words, contains confidential information that would damage the airline.

A NSW Supreme Court judge on Wednesday extended an interim injunction granted on Tuesday preventing Holdforth, a Sydney author, from revealing any contents of her manuscript until the next hearing on 6 July 2015, the Sydney Morning Herald reported.

Holdforth wrote Joyce’s speech delivered on the day he announced his decision to ground the Qantas fleet – an unprecedented action in 2011 to break an industrial dispute. She was also speechwriter for Joyce’s predecessor, Geoff Dixon, and for former Qantas chairman Margaret Jackson, the Herald noted.

The paper cited court documents detailing emails and meetings between Holdforth and Qantas’ head of corporate affairs and marketing, Olivia Wirth and the airline’s senior lawyers.

After reading the manuscript, Wirth considered it “contained information concerning the business, operations and affairs of Qantas that is confidential” to Qantas.

The manuscript reportedly looks at Joyce’s leadership of the airline and Wirth’s command of communications strategy during that turbulent time.

NSW Supreme Court judge Patricia Bergin extended the interim injunction and urged Qantas and Holdforth to enter mediation to avoid a legal battle that would permanently fracture their relationship, the paper said.